The present invention relates to slurry pumps which comprise a hopper, a pumping cylinder communicating at one end with an opening in the hopper, a piston reciprocatable within the cylinder, drive means for reciprocating the piston, a cranked delivery tube have a pivotally mounted portion and drive means for swinging the tube about the axis of its pivotally mounted portion to bring a swinging end of the tube into and out of register with the pumping cylinder.
The moving parts of slurry pumps with swinging delivery tubes present considerable dangers to workmen. Accordingly it is an object of the present invention to provide a safety mechanism whereby the dangers presented by the moving parts are minimised.
A slurry pump having the safety mechanism provided by the invention has a guard having a closed position in which the guard prevents access to a part of the slurry pump, and an open position in which the guard permits access. The pump is characterised by a cam surface which is moved by movement of the guard from its closed position to cause the control member to adopt its neutral position if it is not in its neutral position and thereafter prevents the control member moving from its neutral position until the guard has been returned to its closed position.